carbon monoxide in THF-d8 (tetrahydrofuran-d8); benzene Co-complex was placed in NMR tube, THF-d8 and benzene were distilled onto the sample under vac., tube was sealed under CO (3 atm, at 25°C), allowed to thaw at -78°C, reaction was allowed to proceed at room temp.; monitored by NMR;

carbon monoxide in THF-d8 (tetrahydrofuran-d8); benzene (CpCo(CO)(CH3))2 and (CpCo(CO)(CH3CH2))2 were placed in NMR tube, THF-d8 and benzene were distilled into the tube, tube was sealed under CO (3 atm, 25°C), tube was thawed at -78°C; monitored by NMR;

in deuterated toluene byproducts: acetone; Co-complex was dissolved in toluene-d8, soln. was filtered into NMR tube, was allowed to decompose at room temp.; monitored by NMR;

in THF-d8 (tetrahydrofuran-d8) each Co-complex was dissolved in THF-d8, cooled to -40°C and mixed; monitored by NMR at -50°C;